The present invention relates to a device for heating, ventilating and/or air conditioning the passenger compartment of a motor vehicle, of the type including air treatment means being accommodated, at least partly, in a housing provided with air outlets, the demisting outlet and the aeration outlets opening out in a specifically shaped upper face of the housing and being capable of supplying treated air to at least one demisting vent and aeration vents provided in a fascia of a dashboard via ducts linking the said outlets to the said vents, the said dashboard including an upper fascia and a front fascia.
Nowadays, the air from the air-conditioning apparatus is routed to the demisting and aeration vents via the end-to-end fitting of several pieces which are assembled when the driver""s position is fitted out. Moreover, the aeration vents are usually affixed to the front fascia of the dashboard, within the envelope of the driver""s or of the front passenger""s arm""s reach, and in particular include a central aeration vent situated above the central console, and two lateral aeration vents. These aeration vents, having limited diffusing surface areas, deliver aeration air at high speed. Moreover, the arrangement of the central aeration vent above the central console limits the volume thereof.
The international standard ISO 3958 of Feb. 15, 1996 defines arms""reach zones for the driver of a motor vehicle. These zones are defined as being contained within the outer envelope of two spheres defined geometrically with respect to the driver""s seat. Each sphere corresponds to the range of movement of one of the driver""s hands. The passenger""s arms""reach zones can be deduced by symmetry with respect to the plane of symmetry of the passenger compartment.
The references in FIG. 10 represent the following:
Pbxe2x80x94the outer envelope of the dashboard of a motor vehicle,
Cdxe2x80x94the outer envelope of the range of movement of the driver""s right hand, corresponding to gripping with three fingers,
Cgxe2x80x94the outer envelope of the range of movement of the driver""s left hand, corresponding to gripping with three fingers,
Pgxe2x80x94the outer envelope of the range of movement of the passenger""s left hand, corresponding to gripping with three fingers,
Pdxe2x80x94the outer envelope of the range of movement of the passenger""s right hand, corresponding to gripping with three fingers,
Cgbxe2x80x94the outer envelope of the range of movement of the driver""s left hand, corresponding to gripping by the fingertips,
Cdbxe2x80x94the outer envelope of the range of movement of the driver""s right hand, corresponding to gripping by the fingertips,
Pgbxe2x80x94the outer envelope of the range of movement of the passenger""s left hand, corresponding to gripping by the fingertips,
Pdbxe2x80x94the outer envelope of the range of movement of the passenger""s right hand, corresponding to gripping by the fingertips.
These various spherical envelopes cut the outer envelope Pb of the dashboard along curvilinear lines, which divide the outer envelope Pb of the dashboard into different zones, accessible or not accessible to the fingers of one of the driver""s or passenger""s hands when gripping with three fingers or by the fingertips. These curved lines and the corresponding zones are shown in FIGS. 11a to 11g. 
The zone A1 is the part of the dashboard that lies in the intersection of the envelopes Cd and Pg.
The zone B1 is complementary to the zone A1 in the envelope Pb of the dashboard.
The zone A2 is the part of the dashboard that lies in the intersection of the envelopes Cdb and Pgb.
The zone B2 is complementary to the zone A2 in the envelope Pb of the dashboard.
The zone A3 is the part of the dashboard that lies in the junction of the envelopes Cd and Pg.
The zone B3 is complementary to the zone A3 in the envelope Pb of the dashboard.
The zone A4 is the part of the dashboard that lies in the junction of the envelopes Cd, Cg, Pd and Pg.
The zone B4 is complementary to the zone A4 in the envelope Pb of the dashboard.
The zone A5 is the part of the dashboard that lies in the junction of the envelopes Cdb and Pgb.
The zone B5 is complementary to the zone A5 in the envelope Pb of the dashboard.
The zone A6 is the part of the dashboard that lies in the junction of the envelopes Cdb, Cgb, Pdb and Pgb.
The zone B6 is complementary to the zone A6 in the envelope Pb of the dashboard.
In the above definitions, the vehicle is assumed to have a left-hand driving position. In the case of a vehicle with a right-hand driving position, the words driver and passenger merely have to be interchanged in the definitions.
A first object of the invention is to propose a novel architecture of the means for delivering the demisting air and aeration air which makes it possible to increase the space available above the console in the central instrumentation zone of the driving position.
A second object of the invention is to propose a novel architecture of the means for delivering the demisting air and aeration air which makes it possible to simplify the fitting-out of the cockpit particularly by virtue of a reduction in the number of pieces.
A third object of the invention is to propose a novel architecture of the means for delivering the aeration air which allows a gentle-diffusion mode or a forced-diffusion mode, at the choice of the occupants of the vehicle.
The invention achieves the first two objects due to the fact that the demisting and aeration ducts are formed in an oblong diffusion module which extends transversely above the upper face of the housing and under the upper fascia of the dashboard, this module including an aperture, in its lower face, matching the shape of the upper face of the housing, and, on its upper front edge, the downstream portions of the demisting duct and of the aeration ducts, the downstream portions of the aeration ducts extending transversely on either side of the demisting duct and terminating in aeration vents situated above the zone B4 of the envelope Pb of the dashboard situated outside the intersection A4 of the outer envelopes Cg, Cd, Pg, Pb of the range of movement of the driver""s and passenger""s right and left hands, corresponding to gripping with three fingers, and directed towards the inside of the passenger compartment.
Advantageously, the diffusion module is obtained by assembling two thin-walled pieces. The downstream portions of the aeration ducts are bounded by two parallel walls with a curvilinear section along vertical planes parallel to the median longitudinal plane of the passenger compartment. These two walls feature convex surfaces at the front side of the diffusion module, and are linked by a plurality of vertical partitions.
In order to achieve the third object of the invention, the aeration vents are equipped with an adjustable convergent/divergent system which makes it possible to vary the exit speeds of the air so as to obtain a gentle-diffusion mode or a forced-diffusion mode. In the gentle-diffusion mode, the total diffusing surface area of the aeration vents is at least equal to 2.5 dm2.
The diffusion module advantageously includes distribution flaps for distributing the air taken into the said module between the demisting duct and the aeration ducts.